This multi-part model kit represents the double dome versions of the highly successful 5 inch 54 caliber Mark 42 Mount installed aboard many US Navy and allied warships. The double dome "Frog-Eye" mounts were carried by Forrestal class aircraft carriers, as well as other ships of many navies.

Features:

overall dimensions from official US Navy drawings

barrel slot in trunnion, ready for you own barrels (not inlcuded)

two detailed "frog-eye" local fire control domes (right for antiaircraft, left for surface firing)

From Wikipedia: "The Mark 42 5"/54 caliber gun (127mm) is a naval gun (naval artillery) mount used by the United States Navy and other countries. It consisted of the Mark 18 gun and Mark 42 gun mount. United States naval gun terminology indicates the gun fires a projectile 5 inches (127.0 mm) in diameter, and the barrel is 54 calibers long (barrel length is 5" × 54 = 270" or 6.9 meters.)[1] In the 1950s a gun with more range and a faster rate of fire than the 5"/38 caliber gun used in World War II was needed. Because of this reason, the gun was created concurrently with the 3"/70 Mark 26 gun for different usages. The 5"/54 Mk 42 is an automatic, dual-purpose (air / surface target) gun mount. It is usually controlled remotely from the Mk 68 Gun Fire Control System, or locally from the mount at the One Man Control (OMC) station.[2]"